Reinforced glass and process of making the same



, Ho Drawing.

LEON nnancors Mascaras, or rams, FRANCE, ASSIGNOR To soersrn nu vnam:TRIPLEX, or PARIS, FRANCE.

REINFORCED eLnss AND PRooEss or MAKING THE SAME.

I Appneation' filed March 21 1 TaaZZ whomit may concern: I

1 Be it known that I, 'LnoN Fnangors. Mas- CART, a citizen of theRepublic of France, and a resident of 17 Rue Desnouettes, Paris, France,have invented a new and useful Improved Reinforced Glass and Process ofMaking the Same, of which the following is a specification.

In the manufacture of non-scatterable glass strengthened or-reinforcedby means of a core of celluloid or other similar mate: rial glued to thesheets ofglass by gelatin,

- it is of great importance for effecting the gluing to be able to usenaturally hard gelatin or gelatins artificially hardened, or

tanned or rendered suificientlyinsoluble to resist the destructiveaction of the moisture of the air and able to withstand a'large increaseof temperature without having a ten-. dency to melt or.run.-

This invention relates to improvements, the object of which is theemployment of gelatin in this capacity and in addition to (whatever beits nature and state) notonly to the surfacerof the sheets ofglass,-which does not ofler any serious diificulties when the gelatin isspread on' the glass, but also to the-surfacemf celluloid, celluloseacetate or other cellulose ester or suitable substance iiitended for useas the core of the reinforced ass. g As hereinafter described adhesiontothe glass is obtained in a very simple manner by spreading a layer of anaqueous solution of gelatin on each of the glass sheets (which have beenpreviously properly cleaned) with the use of any productgenerallyemployed for the purpose, and then allowing. the sheets, todry. The layer-of gelatin thus'obtained, can be hardened, tanned orrendered.

insoluble by the Well-known processes (bichrom'ate of potash, formalin,etc). The

chief difficulty met with-which is overcome by. the present invention,consists in insur- 1 mg sufiicient adhesion of the said layer of hardgelatin which has been rendered insoluble to'the celluloid or othercellulose ester intended to form the 'coreof the minforced glass.

Accordingly one of the essential improve- I ments forming the subject ofthe present invention, consists in depositing from its solution a thinlayer ofcellulose on the gelatin in such. condition as to insure itsadhesion to the latter to the required. degree whatever be I its stateof hardness, and in using the aforesaid layer of cellulose as anintermediate substance for insuring the adhesion to the gelatin of theremainder of the celluloid core; this no longer 'ofiersany difliculty,as

it is then merely'a question of making cellu loid adhere to celluloid.In order to carry out the invention on the a top of each layer ofgelatin a solution ofnitro-cellulosecelluloid or other ester ofcellulose (acetate of cellulose) is'uniformly spread and allowed to dry.The layer of cellulose thus obtained, strongly adheres to the gelatin,more particularly if a solvent has'been used which is not very volatile,-such as amyl acetate, but in order to insure satisfactory adhesion inevery case, whatever be the state and the nature of the gelatin,-it isnecessary to add to the solution of the cellulose ester a smallproportion (about 10- 20%) of various substances which havefthe propertyof being common solvents for gela-. tin. and for the cellulose ester,such for ins stance as acetic acid,-acetamid or formamid.

For completing the-manufacture of the reinforced glass two glass sheetswhich have been prepared, as 4 described above, are

dipped into alcohol of strength about 90%" and after bein exposed to atemperature'of about 6070 are pressed one against the other, or beforepressing the sheets together there Although the process just describedseems to be the best for insuring a perfect adhesion of gelatin tocelluloid, experience has shown that very satisfactory results can beobtained even with hard gelatin or gelatin which has been hardened orrendered insoluble by dipping sheets of glass previously. covered withgelatin by spreading as already mentioned, directly into alcohol ofabout 90% strength may be inserted between them a sheet of celluloid'orsome other ester of cellulose inixed with one or more common solventsfor gelatin and celluloid or esters of cellulose (acetic acid, acetamid,formamid, etc.), for instance, for dissolving an ester of cellu- [losein the proportions indicated of about 1020%. This direct dipping intoalcohol prepared in this way takes. the place of the spreading of thesaid alcohol solution; it is then suflicient topress the sheets of glassagainst a core of celluloid or other cellulose .of a san blast.

ester inserted between them, the temperature conditions above referredto being ob-' served.

Another improvement which contributes "to the increased. adhesive powerof a cellu loid sheet to gelatin consists in mechanically or.chemicallyftreating the surface ofthe' 10 celluloid sheet. ;In the'firstcase, the surface is slightl roughened, for instance by means In thesecond case, a reducing reagent, for instance an alkaline sulfid or anyof the reagents proposed for denitrat-. in nitro-cellulose, is used. Thesheet of ca ulose thus mechanically or chemically prepared stronglyadheres to a sheet of gelatin when the two sheets are dipped intoalcoholjand pressed against one another, at

the same time being exposedto the action of heat.

This feature of; mechanicall or chemically treatin the celluloid sheetorms the subject of a ivisional application for atent filed by meSeptember 12, 1918, Serial 0. 253,790.

If instead of using nitro-celluloseor celluloid, sheets of a mlxture ofcelluloid and cellulose acetate, such as are industrially prepared areused, the same process remains applicable. Sheets of cellulose acetateor other similar esters which do not containnitro-cellulose, have theirsurface attacked by a hot alkaline solution and can subsequently betreated in the same manner.

A modification of the process is as follows:

After the surface of the sheet of cellulose ester has been attacked itis dipped into a hot solution of gelatin and left-to dry. The

sheet which is thus coated with gelatin on both sides, is after dryingdipped into alcohol and pressed between two sheets of glass or twosheets of glass .coated with gelatin, under the action of heat, asstated above. I

In all the cases reinforced glass, comprising two sheets of glassand acelluloid core stuck to the glass by means of two layers'of gelatin isobtained; this as the peculiarityof perflect adherence ofroduct howeverthe various portions to one another, even when the layers of gelatin andcelluloid deposited from solution, areexceedingly' thin, (for instance0.001 mm.).

In the same way there could be manufactured reinforced glass com risingany desired number of glass, plates, 'oth greater and less than two.

More particularly, whenit is desired to manufacture a. productconsisting of a single sheet'of glass, to which is lued, by means ofgelatin, a sheet of cellulold, it is sufficient to. stop the operation'at the moment when the cellulose layer has been spread on the layer ofgelatin. If it is considered that that it 'should be incom'bustible.

this layer is not sufliciently thick, then one or more layers obtainedin'the same manner could be superposed on it.

Glass prepared'in his manner has a solid- 7 ity which makes it a realreinforced glass, suitable, for certain applications. If the elatin hasbeen-suitably hardened and renered insoluble, it' resists the action ofwater and heat, and can be used just as it is. The

layer of cellulose must not be too thin; it

must be at least 0.10.2 mm; thick in order v to form a suflicientlystrong core. Finally,

as this core is exposed, it is very important 7 2. The process ofreinforcing glass'which comprises the step of forming a film of gelatinupon the face of a sheet of (glass from a gelatin solution, permittingsai film to dry,

and then superposing on said film a film of cellulose ester in the formof a solution, the solvent employed being common to both the gelatin andthe celluloseester, whereby an intimate union between the films issecured,

permitting said films to dry and then pressing a' relatively strongsheet-of cellulose ester against the same in'the presence of heat, forthe purpose described. 1

- 3. The process of reinforcing glass which comprises the step offorming a film of elatin upon thejface of a sheet of glass rom a gelatinsolution, permitting said film to dry,

gelatin" and thecellulose ester, whereby an intimate union between thefilms is secured,

and then superposing on said film a film of cellulose ester in the formof a solution, the solvent employed being common to both the permittingsaid films to dry and then pressj ing a relativel [strong sheet ofcellulose ester against t e samein, the presence of heat and alcohol,for the purpose described.

4. The process of reinforcing glass which comprises the step of forminga film of gelatin upon the face of a sheet of glass from a gelatinsolution, permitting said film todry, and then superposing on said filma film of cellulose ester in the form of asolution, the solvent employedbeing common to both the gelatin and the cellulose ester,

whereby "an intimate union between the films 1s secured permitting saidfilms to dry and then presslng a relatively strong sheet of celluloseester against the same in the presence of heat, the adherent surface ofthe said sheet having, been previously treated to more readily unitewith said films under the pressure exerted.

5. The process of reinforcing glass which comprises the step of unitingthereon a layer of. gelatin and a layer of cellulose ester, said unionbeing accomplished in the presence of it solvent common to said gelatinand celluose. 1

6. As a new article of manufacture, a sheet of cellulose ester faced onbothsides and in theorder named by a film of cellulose ester, a'film ofgelatin united thereto in the presence of a common solvent, and a sheetof glass, all rigidlyand autogeneously united together.

7. The process of making non-scatterable glass which comprises applyingto a sheet of glass successively'a solution of gelatin and a solutionofcellulose material, at least one of said'solutions containing asolvent which.

has a solvent action upon both the gelatin 'and the cellulose material.

8. The process of making non-scatterable glass which comprises coatingsheets of glass with gelatin,- then applying to such coating a solutionof cellulosic material and thereafter'pressing a sheet of celluloid3-bethween the coated faces of two such glass s eets.

9; The process of making non-scatterable glass which comprises coatingglass sheets With hard gelatin, applying to each such coating a layer ofcellulose materialin the presence of a solvent of both the gelatin andcellulose material, and thereafter pressing between two such coatedglass sheets a sheet of celluloid.

10. The process of making non-scatterable glass, winch comprisesapplying a layer of gelatin to a glass sheet, coating such layer with asolution of cellulosic material and al lowing, same to dry, and thenpressing between two such coated glass sheets a sheet of celluloid,after treating the sheets'.with

alcohol. s s g v 11. The process of making non-scatterable glass whichcomprises applying to a sheet of glass a gelatin coating and applying tosaid gelatin coating a coating of cellulosematerial, there. beingpresent in the region of contact of the two coatings a solvent for both.

12. The process of making non-scatter able glass, which comprisescoating a sheet of glass with hard gelatin, and then applying to saidgelatin layer a coating of cellulose material, there being present inthe re- 7 region of contact by a common solvent, anda protectivematerial covering. said film of cellulose material.

15. -As a new article of manufacture, reinforced glass, comprising asheet of cellulosic material, faced on each side by layers of saidmaterial and gelatinous material and a sheet of glass all firmly adheredtogether.

In testimony whereof I sign my name to this specification in thesubscribing witnesses.

LiioN FRANQOI S MASOART. Witnesses CHASQ'P. PRESSLY, LEON TEImJE'r.

presence of two

